Reprinted: SHUMLA . Lewis Canyon Petroglyph Site – Gigapan Images. Past Horizons. August 22, 2013, from http://www.pasthorizonspr.com/index.php/archives/08/2013/lewis-canyon-petroglyph-site-gigapan-images
|Extreme polecam, Copyright (c) Mark Willis and The Shumla School, Inc. 2013.|
Lewis Canyon Petroglyph Site is located in the Lower Pecos Region of Texas and situated on a near flat stretch of limestone bedrock adjacent to a steep walled canyon. Hundreds or maybe thousands of prehistoric petroglyphs were carved into the rock in this area.
Creating a map of the site
Some of the designs appear to resemble atl atls (a dart throwing weapon), human-like figures, animals and animal tracks but the most common elements are abstract circles, lines, and dots.
A revolutionary technique was used to map the area so it can be seen as a single Gigapan image, which can be zoomed into at incredible detail.
A group of five archaeologists walked a series of transects holding a Canon digital SLR camera on the end of a painter’s pole, taking photos straight down at about every 2.5 metres across the entire site. The surface is more than 175 metres (~600 feet) east/west by 160 metres north/south (~525 feet). A total of 2,400 images were used to create this mosaic.
On closer inspection, the viewer will note the eastern half of the site was photographed at dusk on one day and the western half after dawn on the next day. This was done to capture the petroglyphs with the strongest shadows possible and from the best angle that the two sides of the site required.
A huge single image
All of the photographs were then processed as a mosaic image using an advanced photogrammetric technique and exported into GIS software and geo-corrected. The data was further enhanced and turned into a huge single image 135 gigabytes in size. This was down sampled so that there is a single pixel in the Gigapan for every millimetre of ground surface. The resulting image was then uploaded to Gigapan.com for others to examine.
Archaeologists have been drawn to the site since it was discovered. A number of well-known rock art researchers, artists and archaeologists have studied the petroglyphs including Forrest Kirkland, A.T. Jackson, Solveig Turpin, and Jim Zintgraff. The new researchers hope this digital documentation will help others better understand this amazing resource.
|Some of hundreds of petroglyphs and geoglyphs covering the survey area.survey area. Copyright (c) Mark Willis and The Shumla School, Inc. 2013.|
Extreme pole aerial photography
View the Gigapan image here: http://www.gigapan.com/gigapans/136529
Once opened, click on the “Snap Shot” icon on the lower left, it will open a strip of images along the bottom. If you double click on a image it will zoom to that spot.
|Extreme polecam, with 2400 images covering the survey area. Copyright (c) Mark Willis and The Shumla School, Inc. 2013.|
If you would like to learn more about this site or visit it, the Rock Art Foundation can help: www.rockart.org.
Copyright (c) Mark Willis and The Shumla School, Inc. 2013. All rights reserved. No part of this information and imagery may be reproduced, stored in a retrieval system, or transmitted in any form or by any means without the prior written permission of Mark Willis or Shumla.
Source: SHUMLA and Mark Willis